Fluidic devices having acoustic wave sensors for detecting the presence of an analyte in a sample often have biomolecules, such as antibodies or other proteins such as receptors, polynucleic acids, or the like attached to their surfaces. The analyte may bind to the biomolecule attached to the surface of the sensor and increase the mass bound to the sensor. The increased mass alters the wave propagation characteristics (e.g., magnitude, frequency, phase, etc.) of the sensor. The change in propagation characteristics due to analyte binding may be correlated with the amount of bound analyte and, thus, the amount of analyte in the sample.
Many fluidic acoustic wave sensor devices have a cover over a channel through which fluid containing an analyte may flow. A surface of the sensor to which the biomolecule is attached may be exposed to the channel to allow analyte to bind the biomolecule as the fluid flows over the sensor.
The cover is typically placed over the channel after the sensor is functionalized (the biomolecule is attached to the sensor). Once the surface of the sensor is functionalized with the biomolecule, further processing of the sensor or fluidic device should be performed at low temperatures, such as temperatures below 40° C., to limit damage to the biomolecules. Accordingly, higher temperature processing steps to attach the lid over the channel are preferably avoided.
One commonly used low-temperature bonding approach is the use of ultraviolet (UV)—curable epoxy. However, exposure of biomolecules to UV radiation may also degrade or adversely alter the biomolecule.